Asthma is a very common disease in the United States and other industrialized countries, affecting more than 5% of the population. Key features of asthma are airway smooth muscle hyperreactivity, leading to variable airflow obstruction; infiltration of the airway wall with inflammatory cells, most notably helper T-cells (Th2) lymphocytes and cosinophils; and structural changes, such as metaplasia of the airway epithelium from non-secretory ciliated cells to mucus-secreting goblet cells and thickening of the sub-epithelial basement membrane.
Most asthmatics have mild disease that is controlled with low doses of inhaled corticosteroids to suppress inflammation, and inhaled β2-adrenoceptor agonists to relax airway smooth muscle. However, even low doses of inhaled steroids cause systemic side effects, such as growth suppression in children and cataracts in adults. Further, approximately 15% of asthmatics have severe disease that can lead to disability or death despite treatment with high doses of steroids. Thus, safer and more effective treatments for asthma are needed.
Lactoferrin is a single chain metal binding glycoprotein. Many cells types, such as monocytes, macrophages, lymphocytes, and brush-border cells, are known to have lactoferrin receptors. In addition to lactoferrin being an essential growth factor for both B and T lymphocytes, lactoferrin has a wide array of functions related to host primary defense mechanisms. For example, lactoferrin has been reported to activate natural killer (NK) cells, induce colony stimulating activity, activate polymorphonuclear neutrophils (PMN), regulate granulopoeisis, enhance antibody-dependent cell cytotoxicity, stimulate lymphokine-activated killer (LAK) cell activity, and potentiate macrophage toxicity.
EDTA (ethylenediaminetetraacetic acid) is a synthetic compound which has well known metal-binding characteristics. EDTA is most commonly used for chelation therapy, a treatment that involves repeated intravenous administration of EDTA to pull toxins from the bloodstream. EDTA administration is the medically accepted treatment for poisoning by heavy metals such as lead, mercury, arsenic and thallium and has been approved by the Food and Drug Administration (FDA) for this use.
EDTA has also been proposed as a treatment for heart disease. Proponents of chelation therapy for heart disease claim that EDTA, in combination with oral vitamins and minerals, helps dissolve plaques and mineral deposits associated with atherosclerosis. Although many Americans with heart disease have turned to EDTA chelation therapy to improve their condition, the FDA has not approved this therapy as an alternative treatment for heart disease. It is thought that EDTA chelation may help strengthen the immune system by sequestering impurities from the bloodstream. EDTA is not known to cause any significant side effects when administered orally to humans.
The present invention is the first to use an oral lactoferrin composition as a treatment for allergic respiratory disorders, such as asthma. Yet further, the present invention is the first to use lactoferrin in combination with a metal chelator to treat respiratory disorders, such as asthma.